This invention relates in general to a seat that is movable relative to an ancillary structure, such as a vehicular seat that is movable relative to an airbag mechanism. In particular, this invention relates to an improved sensor assembly for use with such a relatively movable seat that can simply and inexpensively maintain a predetermined distance between sensor and target portions thereof.
In many environments, a seat is supported for movement relative to an ancillary mechanism. For example, in many vehicles, the driver or passenger seats of the vehicle are movable in both forward and rearward directions relative to an airbag mechanism or other supplemental restraint system that is provided within a steering wheel or an instrument panel. Such a movable seat is usually provided to facilitate comfort of an occupant of the seat within the particular environment.
In some of these environments, it may be desirable to control the operation of the ancillary mechanism in accordance with the position of the movable seat relative thereto. For example, in a vehicle having a movable seat, it may be desirable to control the operation of the airbag mechanism in accordance with the relative position of the movable seat. As is well known, a typical airbag mechanism includes a flexible bag that is rapidly inflated in response to the occurrence of a predetermined event, such as a collision, in order to cushion an impact that might otherwise occur to the occupant. In certain instances, it may be desirable to control the rate at which the flexible bag is inflated or the total volume of such inflation in accordance with the position of the movable seat (and the occupant) relative to the airbag mechanism.
To accomplish this, it is known to provide a sensor assembly that can generate a signal that is representative of a position of such a relatively movable seat. A typical sensor assembly includes a sensor portion, which is supported on one of the movable seat and a support surface, and a target portion, which is supported on the other of the movable seat and the support surface. When the seat is moved relative to a predetermined position relative to the support surface, the sensor portion detects the target portion and generates a seat position signal. This seat position signal is fed to a controller that operates the airbag mechanism. The controller can be responsive to the seat position signal to control the rate at which the flexible bag is inflated or the total volume of such inflation in accordance with the position of the movable seat relative to the airbag mechanism.
In such sensor assemblies, it is often desirable to maintain a predetermined distance between the sensor portion and the target portion. Although known sensor assemblies have functioned satisfactorily, it has been found that the distance between the sensor portion and the target portion may vary undesirably as a result of tolerance variations in the assembly of the various components of the movable seat and for other reasons. Thus, it would be desirable to provide an improved sensor assembly that can simply and inexpensively maintain a predetermined distance between the sensor and target portions thereof.